Shale Formations Connected To Aquifers

Pathways exist that would allow migration of methane, brines, or fracturing fluids from deep Marcellus Shale gas formations to shallow drinking water aquifers, according to a new study (Proc. Natl. Acad. Sci. USA, DOI: 10.1073/pnas.1121181109). Geologists at Duke University and California State Polytechnic University, Pomona, examined geochemical evidence in northeastern Pennsylvania. They found that migration of naturally occurring Marcellus brines and other materials has taken place through natural hydraulic connections between 1-mile-deep geological formations and shallow aquifers. These pathways predate the current shale fracturing activities occurring in the area, the study notes. The study examined three aquifers and analyzed 426 groundwater samples and 83 deep-formation brine samples. The researchers found compounds from the brine in the groundwater. They noted the increasing concern of communities in the region over contamination of drinking water from natural gas exploration in the area, but the study did not demonstrate that methane or drilling fluids are in aquifers.